Stabilizer lock



Aus 24 1926.

P. G. ZIMMERMANN STABILIZER LOCK @y 3%@ Arron/ver Aug. 24 1926.

P. G.l ZIMMERMANN STABILIZER Locx Original Filed July l1. 1923 2Sheets-Sheet 2 INVENTR BY Arron/ver Patented Aug. 24, 1926.

UNITED STATES PATENT OFFICE.

PAUL G. ZIMMEBMANN, OF KEYIPORT, NEW JERSEY, ASSIGNOB TO AEBOMABINEPLANE 66 MOTOR COMPANY, 0F NEW YORK, N. Y., A CORPORATION OF NEW YORK.

STABILIZEB LOCK.

Application tiled July 11, 1923,'Seria1 No. 650,769. Renewed January 23,1826.

The invention relates to airplanes; and it comprises a limit lock for acontrol surface, particularly for an adjustable stabilizer, so that, inevent of failure of the adjustable device securing the stabilizer, thelatter will become automatically locked against movement in eitherdirection.

In the accompanying drawing illustrating the invention:

Fig. 1 is a side elevation of the horizontal. and vertical stabilizer,with the covering on the vertical stabilizer broken away to show in fulllines the adjusting and locking means for the horizontal stabilizer;

Fig. 2 is a fragmentary side elevation on a larger scale; and

Fig. 3 is a longitudinal section onthe line 3 3 of Fig. 2, showing theposition the parts assume when the horizontal stabilizer is lockedagainst movement in either direction.

The 'drawing shows the horizontal stabilizer 2, and the fixed fin, orlvertical stabilizer, 3 of a flying-boat. The frame 4 of the finconstitutes a supporting frame beneath the 'horizontal stabilizer, whichwill be termed simply the stabilizer, and which in this instance ishinged at its trailing edge to the rear part of the fin, as indicated at5.

A vertical rod o is guided in the frame of the iin and pinned at itsupper end to the forward part of the stabilizer, and its lower portion 7is screw-threaded and carries-a nut 8 in the form of a drum. This drumis held in a recess 9 of the fixed frame against movement either up ordown, and may be operated through a control band (not shown) to raise orlower the rod 6, so as slightly to vary the angle of the stabilizer inorder to trim the flying machine longitudinally.

A short lock rod 10, adjacent and parallel with the rod 6, is alsopinned at its upper end to the stabilizer, and slides in bearings 11 and12 on the fixed frame. Pinned to this rod between the bearings is acollar 13 carrying downwardly extending spring blades 14. Thesebladesare tensioned to spring outwardly, but are normally confined in thebearing l2 forming the lower part of the guide. The arrangement is suchthat the lock rod will slide up or down freely when the stabilizer isadjusted within the intended, limited range, but should the stabilizertend to swing upward in an extreme manner, as the result ot' breakage ofthe adjustable support or otherwise, the lock rod will become fixed andhold the stabilizer against further movement either up or down. i

In the illustrated construction this results from the tips of the blades14 springing slightly outward from the confinement of the bearingpassage into a cup 15 at the top of the bearing 12, at or immediatelybefore the moment when the shoulder of the collar 13 abuts against thebottom of theV upper bearing 11. The cup 15 confines the blades in theirlocking position, and by resting against the ledge at the bottom of thecup they rigidly resist any downward movement of the rod and stabilizer.The latter is thus held ixedly in a safe position.

The foregoing constitutes a simple and preferred embodiment of theinvention, but I wish it to be understood that I do not limit myselrl tothe precise construction as various forms oi' the limit lock which I re-`gard as my invention may bedevised.

lVhat I claim as new is:

1. A lock for a movable control surface comprising a vertical lock rodconnected to the surface', a support having a guide in which said rodcan slide with the movement of the surface, the rod having a shoulder toabut a' portion of the support at the limit of permitted upwardmovement, and spring blade means on the rod adapted to snap out fromconnement in the guide at such limit so as to prevent downward movement.

2. In an airplane having a movable stabilizer, a fixed frame, andadjustable securing means for t-he stabilizer, a lock rod connect ed tothe stabilizer and guided in the fixed frame, and a spring catcharranged to act when the lock rod is raised to a predetermined extent.

3. In an airplane, the combination with a movable stabilizer, a fixediin beneath the stabilizer, and means adjustably securing the stabilizerto the n, of a limit lock between the stabilizer and the tin permittingintended movement of the stabilizer and operative at a predeterminedelevation to cause the stabilizer to be thereafter held against movementin either direction.

PAUL G. ZIMMERMANN.

